/// Copyright (c) 2020 Razeware LLC
///
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights
/// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
/// copies of the Software, and to permit persons to whom the Software is
/// furnished to do so, subject to the following conditions:
///
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
///
/// Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,
/// distribute, sublicense, create a derivative work, and/or sell copies of the
/// Software in any work that is designed, intended, or marketed for pedagogical or
/// instructional purposes related to programming, coding, application development,
/// or information technology.  Permission for such use, copying, modification,
/// merger, publication, distribution, sublicensing, creation of derivative works,
/// or sale is expressly withheld.
///
/// This project and source code may use libraries or frameworks that are
/// released under various Open-Source licenses. Use of those libraries and
/// frameworks are governed by their own individual licenses.
///
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
/// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
/// THE SOFTWARE.

import Foundation
import PencilKit
import CoreML

struct Drawing {
  // MARK: - Properties
  private static let ciContext = CIContext()
  let drawing: PKDrawing
  let rect: CGRect
  
  var featureValue: MLFeatureValue {
      // Get the model's image constraints.
      let imageConstraint = UpdatableModel.imageConstraint
      
      // Get a white tinted version to use for the model
      let preparedImage = whiteTintedImage
      
      let imageFeatureValue = try? MLFeatureValue(cgImage: preparedImage, constraint: imageConstraint)
      return imageFeatureValue!
  }
  
  private var whiteTintedImage: CGImage {
    let ciContext = Drawing.ciContext
    let parameters = [kCIInputBrightnessKey: 1.0]
    let image = drawing.image(from: rect, scale: UIScreen.main.scale)
    let ciImage = CIImage(
      cgImage: image.cgImage!)
      .applyingFilter("CIColorControls", parameters: parameters)
    return ciContext.createCGImage(ciImage, from: ciImage.extent)!
  }
}
